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Changes Introduced in V1.2

The following describes the most significant changes which occurred in the AST library between versions V1.1 and V1.2 (not the most recent version):

  1. A new function, astPolyCurve, has been introduced to allow more efficient plotting of multiple geodesic curves ([*]).

  2. A new set of functions, astResample$<$X$>$, has been introduced to perform resampling of gridded data such as images (i.e. re-gridding) under the control of a geometrical transformation specified by a Mapping.

  3. The command-line options ``$-$pgp'' and ``$-$pgplot'', which were previously synonymous when used with the ``ast_link'' and ``ast_link_adam'' commands, are no longer synonymous. The option ``$-$pgp'' now causes linking with the Starlink version of PGPLOT (which uses GKS to generate its output), while ``$-$pgplot'' links with the standard (or ``native'') version of PGPLOT.

  4. The function astMapBox has been changed to execute more quickly, although this has been achieved at the cost of some loss of robustness when used with difficult Mappings.

  5. A new value of ``FITS-IRAF'' has been introduced for the Encoding attribute of a FitsChan. This new encoding provides an interim solution to the problem of storing coordinate system information in FITS headers, until the proposed new FITS-WCS standard becomes stable.

  6. When a FrameSet is created from a set of FITS header cards (by reading from a FitsChan using a ``foreign'' encoding), the base Frame of the resulting FrameSet now has its Domain attribute set to ``GRID''. This reflects the fact that this Frame represents FITS data grid coordinates (equivalent to FITS pixel coordinates--see [*]). Previously, this Domain value was not set.

  7. astFindFits now ignores trailing spaces in its keyword template.

  8. astPutFits now recognises ``D'' and ``d'' as valid exponent characters in floating point numbers.

  9. The FitsChan class is now more tolerant of common minor violations of the FITS standard.

  10. The FitsChan class now incorporates an improved test for the linearity of Mappings, allowing more reliable conversion of AST data into FITS (using ``foreign'' FITS encodings).

  11. Some further improvements have been made to the algorithms for simplifying compound Mappings, as used by astSimplify.

  12. A new UnitRadius attribute has been added to the SphMap class. This allows improved simplification of compound Mappings (CmpMaps) involving SphMaps and typically improves performance when handling FITS world coordinate information.

  13. A MatrixMap no longer propagates input coordinate values of AST__BAD automatically to all output coordinates. If certain output coordinates do not depend on the affected input coordinate(s) because the relevant matrix elements are zero, then they may now remain valid.

  14. A minor bug has been corrected which could cause certain projections which involve half the celestial sphere to produce valid coordinates for the other (unprojected) half of the sphere as well.

  15. A bug has been fixed which could occasionally cause astConvert to think that conversion between a CmpFrame and another Frame was possible when, in fact, it wasn't.


next up previous 264
Next: Changes Introduced in V1.3
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AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council